Cement finishing machine



March 18, 1958 R. L. STEVENS 2,826,972

CEMENT FINISHING MACHINE Filed April 9,'1954 s sheets-sheet 1 1N VEN TOR. Race-nr l srfvEN:

A rromvfvs March 18, 1958 R. L. STEVENS 2,826,972

CEMENT FINIsHING MACHINE 5 Sheets-Sheet 2 v Filed April 9. 1954 INVENTUR 80.567 L. Srfvews BY @4440,MM1

/qrransrs Y March 18, 1958 R. STEVENS 2,826,972

CEMET FINISHING MACHINE 3 Sheets-Shee't 5 Filed April 9, 1954 v IN VEN TOR Roten-r Srs veA/s BY @Mu/,MMvQ-m.

United States Patent O CEMENT FINISHING MACHINE4 Robert L. Stevens, Boston, N. Y., assignor to Wiesner- Rapp Company, Inc., Buffalo, N. Y.

Application April 9, 1954, Serial N o. 422,028

Claims. (Cl. 94-45) My invention relates in general to machines for treating the surface of cementitious bodies, and in particular to a troweling device for floating and linishing cement floors and the like.

In troweling cementitious surfaces, it is known vthat the troweling action preferably begins at a relatively slow surface speed and that during this stage of the operation the trowels are arranged at a small angle or pitch with the surface being treated. However, as the cement mixture hardens, it is desirable not only to increase the surface speed of the trowels but also to increase the angle of incident of the trowel with the cementitious surface. Since it is desirable that the changes of speed and angular relation of the trowels with the cementitious surface being treated shall be accomplished during the treatment and as the cement is hardening, it is a principal object of my invention to provide a trowel which can have its speed of rotation and trowel angle changed to Vsuit the hardening conditions of the cementitious body while in operation.

Another object is to provide centrifugal means connected to the trowel blades and so arranged that an increase of speed of `said centrifugal means will cause an increase of the angle of the blades with the surface being treated.

A further object is to provide a device in which the trowels are mounted for independent movement so that if one trowel encounters a stone the angle or position of the other trowels will remain unchanged.

Moreover, the trowels of my device are supported by shock absorbers to cushion the shock upon any individual trowel upon striking a stone or other protruding objects in the cement mixture.

The above objects and advantages have been accomplished by the device shown in the accompanying drawings, of which:

Fig. l is a side sectional elevation kof my complete device;

Fig. 2 is a fragmentary plan sectional view taken on line II-II of Fig. 1;

Fig. 3 is an enlarged sectional view taken through one of the blades and shock absorbers on line III- III of Fig. 2;

Fig. 4 is a fragmentary side elevation of a modified form of device;

Fig. 5 is a fragmentary plan view of the device shown in Fig. 4; and,

Fig. 6 is an end elevation, partly in section, of the form of deviceshown in Fig. 4.

Referring now to the form of invention shown Figs. 1 1tof3, inclusive, the device comprises a main casing 10 having a top wall 11 and al bottom plate 12. Rotatably mounted within the top ,wall and the bottom plate` of'the casing is afmain shaft 13. The shaft is mounted in suitable bearings and is formed near its lower-wend with'a langev 14 to which is attached the drivingdisclS of the device. The disc is nonrotatably secured to the drive shaft by means of a key pin 16.

ICS

Mounted upon the top wall of the casing is a gear support 20 within which is rotatably mounted a gear shaft 21, having a driven bevel gear 22 at its upper end and a driving sprocket 23 at its lower end. The driving sprocket is connected to a driven sprocket 24, carried by the main shaft 13, by means of a sprocket chain 25. The gear 22 is actuated by a driving gear pinion 26 which is carried by a pinion shaft 3Q rotatably mounted Within a gear casing 31 and driven by means of a driven sheave 32 carried at the outer end of said shaft. An internal combustion engine 33, or other suitable form of motive power, is carried by the top wall 11 of the main casing and has its drive shaft 34 connected to the driven sheave 32 by means of a belt 35 which passes over a drive sheave (not shown) carried by the engine shaft.

Carried by the driving disc 15 is a plurality of radiatingarms or spokes 36. The spokes are secured preferably to the under side of the disc and form the trowel supports. A trowel 40 is positioned under each of the spokes 36 and is formed with an upstanding trowel bar 41. The trowel bar is detachably secured to a trowel yoke 42 by means of screws 43. The trowel bar is preferably located centrally of the longitudinal width of the trowel, whereby the trowel may be reversed when one edge becomes worn.

Each of the trowel yokes 42 is connected to one of the spokes 36 by means of shock absorbers 44. Each of the shock absorbers comprises a casing 45 formed with a longitudinal aperture 46. The aperture 46 extends to a point near the bottom of the casing where it meets and joins a reduced aperture 50. The lower end of the casing is formed in its wall with oppositely arranged elongated openings 51, and a trowel pivot pin 52 is disposed in the openings and passes through oppositely arranged abutment lugs 53 carried by the yoke, by which the yoke is rigidly supported. A spring plunger 54 is mounted within the aperture of each of the shock absorber casings 45l and each is provided with a reduced portion 55 engaging the reduced aperture 50 and bearing against the top surface of the pivot pin 52. A reduced portion 56 is also formed at the upper end of the plunger for the reception of a helical spring 60 which is mounted within the aperture 45 of the casing and which is retained in position by means of a spring plug 61 held in place by a retaining pin 62. This arrangement permits the trowel pivot pins to move upwardly against the compression of the helical springs 60 when the trowel is passing over a protruding stone or other object in the surface of the material being treated.

Each of the trowel yokes is actuated by means of a weight 63 carried at the outer end of a weight arm 64 pivotally attached to its respective spoke by means of a l pivot bolt 65. Secured to each of the trowel yokes is a tilting arm 70 which is connected to the weight arm 64 of the next preceding spoke by means of a tilting rod 71. The rod is pivotally attached to the weight arm by means of a clevis 72 and to the tilting arm by means of a universal connection 73. As each weight is moved outwardly, the centrifugal action, as the spokes are rotated, each trowel will be actuated to its angular position by the next preceding weight.

In order that the weights be retracted to their normal position when the device is idle, I provide suitable retracting means 114 connecting the spoke with the weight arm.V

These means may comprise a housing 115 pivotally attached to the weight arm and carrying a helical spring 116. A spring rod 117 is centrally supported by a collar 118 arranged at the outer end of the casing. A collar 119' is secured at the inner end of the rod and the spring, disposed within the housing, has one end bearing against the collar 119 and the other against the collar 118, where- `by the rod will normally be drawn into the casing. The

froid 117 is pivotally securedlto 'the coacting spoke 36. In order to limit the expansive movement of the retaining means, a tube 121 is placed about the rod and within the spring, whereby when the parts have been separated the predetermined amount, `the tube will act as a stop between the collars 118 `and 119, and thereby limit further outward movement of the rod.

A guard rail 74 surrounds the device and extends beyond the trowels and spokes. This guard rail is supported by means of guard rail arms 75 which are secured to a `guard rail ring 76 secured tothe main casing. A handle 80 is secured to the guard rail ring and is provided with a cross member 81 at its upper end. A throttle lever 82 is provided for controlling the speed ofthe internal combustionengine in wellaknown manner, and a control lever 87 is `also carried by the handle which is within easy reach of the operator and which is connected by a rod 83 to suitable clutch means (not shown) for connecting and disconnecting thezy power means.

Referring now to the form of invention shown in Figs. 4 to `6, inclusive, `each ofthe spokes 84 is connected to the trowel yoke 85 by means of a hinge link 86 at Aits inner end and by means of a combined weight and hinge link 87 at `its outer end. The hinge link 86 is pivotally secured near one end to the spoke by means of a hinge pin 90. An outwardly extending arm 91 is provided at this end of the linkto whichone end `of a retention spring 92 is attached. The other end of the spring is attached to a pin 93 carried by the spoke. This hinge link is also formed with a stop 96 `which isbrought into `engagement with the side surface .of the spoke when the trowel has been extended to its maximum `position by the centrifugal action of the combined weight and hinge link` 87. The hinge link 87 is secured to the outer end of the spoke `by means of a hinge pin 94 and is provided withta weighted portion 95 which is caused to `rotate about its pivot in clockwise direction when the actuating disc is rotated. The weighted portion 95 is formed with a stop 96 which engages the spoke when the weight drawn to its normal retracted position by means of the spring 92. The outer ends of the hinge link 86 and the combined weight and hinge link 87 are pivotally attached to the trowel yoke 85 by means of shock absorber rods One of these rods passes through an enlarged portion formed at the outer end of each of the linksand through acounterbore 101 formed in the enlarged portion for the reception of a shock absorber spring 102. The lower end of the rod isprovided with a shock absorber plunger 103 which engages the counterbore 101 to guide it in its vertical movement. A stop collar 104 issecured to the upperi end of thcrod, whereby the `rod .and` plunger are maintained in neutral position. Each trowel, however, is biased bythe compression of the springs so that it may be independently actuated when it is brought in contact with a stone 'or other object projecting above thenormal` working surface of the cementitious mass.

From the foregoing it will be understood that as the disc is rotated the trowels will lbe moved outwardly in parallel relation with the spokes by movement` of the weights as they are rotated in clockwise direction. Connecting each spoke withthe associated trowel yoke is` aspreader link 105 having one `end secured to a spreader link standard 106 carried by the spoke `and the opposite end connected to a spreader linkstandard 110 carried by the trowel yoke.

The spreader link is preferably secured to the standards by means of well known ball and socket joints whereby universal` rocking movement of the parts is permitted. The spreader link, as shown in Fig. 5, is arranged at an angle tothe spoke whereby `as the trowels are moved outwardly to the dot and dash line of Fig.5, the spreader link standard 110 carried bythe trowel yoke will be'forced outwardly away from the associated spoke, thereby causing the yoke to tilt and consequentlyraising the trowel so as to present it at an angle to the surface being treated. Obviously, lthe faster the disc is rotated, the greater will be the Icientiifugal actin"`prbdu`ced"by':the weightsand consequently the `greater distance of movement thereof. Increased movement of the weights will increase the travel of the yoke and trowel and, therefore, increase the angle of incident of the trowel with the surface of the cement.

When the device shown in Figs. 1 to 3 is to be put into use, the power is connected to the main shaft 13 by means hereinbefore described, and `the disc 15 with its spokes 36 will be rotated in the direction indicated by the arrow in Fig. 3. Each of the weight arms 64 will 1thus be rotated about its pivotal connection due to the centrifugal force exerted upon the weights, andthe tilting rod 71 will be moved axially thereby tilting the arm 70, and the trowel blade connected therewith, as clearly shown in Fig. 3 by the dotted lines. Obviously, the amount of tilt will depend upon the amount of movement of the tilting rod which is governed by the motion of the weight arm 64 and which motion will depend upon the speed of rotation.

In both forms of the invention, n ot onlyfthe surface speed of the troweling action but also 'the angle of the trowels with respect to the surface being treated can be accurately and conveniently adjusted while Vthe device is in motion and without having to interrupt the troweling action.

Obviously, lsome modifications of `the details herein shown and described may be made without departing from the spirit of my invention or the scope of the appended claims.

What is `claimed is:

l. In a cement finishing machine, the combination with a housing and power means carried by the housing, of a rotatable head carried by the housing and connected to the power means, a plurality of radially arranged spokes carried by the head, a trowel yoke disposed below each of the spokes, a trowel secured to the yoke, meanscarried by each spoke for pivotally mounting one of theyokes, a weight arm pivotally carried by each of the spokes, a weight carried by each arm, and means connecting each weight arm with one of the trowel yokes, whereby the yoke will bev oscillated by the centrifugal force exerted upon the weight.

2. In a cement finishing machine, the combination with a housing and power means carried by the housing, of a rotatable head carried by the housing and` connected to 'the power means, a plurality of radiallyarranged spokes carried by the head, a trowel yoke disposed beloweach of the spokes, ua trowel secured to the yoke, means carried byf'each spoke for pivotally mounting-one of the yokes,

-a weight armpivotally 'carried by each of the spokes, a weight carried by each arm, and means connecting each weight'arm with the next succeeding trowel yoke to `cause the yoke to be oscillated by centrifugal force exerted upon the weight.

3. In a cement finishing machine, the combination with a housing and power means carried by the housing, of a rotatable head carried by the housing and connected to the power means, a plurality of radially rarranged spokes carried by the head, a trowel yoke disposed below each of the spokes, a trowel secured to the yoke, means carried by each spoke for pivotally mounting one' of the yokes, `a weight arm `pivotally carried by \each of the spokes, a weight carried by each arm, a tilting arm carried by each of the `yokes, and a tilting rod1connectingach of the arms with the weight arm of the next preceding spoke.

4. The combination in a cement finishing machine having@ rotayheadof aplurality of truwelu'nits, each unit comprising -a trowel yoke pivotally carried by` said head, a trowel carrieduby Vsaid yoke, a centrifugal weight associated with each trowel, each yoke having an npstanding tilting arm, and a tilting rod connecting said weight with the tilting arm of the next succeeding unit.

5. `The combination in a cement finishing `machine having a rotating head, of a plurality of trowel units,

References Cited in the tile of this patent UNITED STATES PATENTS Boulton Feb. 15, 1938 Whiteman Apr. 30, 1940 Conway Mar. 24, 1942 Huiman May 3, 1949 Boulton Aug. 5, 1952 Ytterberg Oct. 6, 1953 

